1. Field of the Invention
The present invention, in general, is related to multi-stage centrifugal compressors and, more particularly, to a diaphragm assembly for use with a multi-stage centrifugal compressor.
2. Description of Related Art
Multi-stage centrifugal compressors are well-known in the art. A typical multi-stage centrifugal compressor includes a compressor casing that accommodates a series of diaphragms, and a rotor in the form of a shaft with impellers installed thereon. The diaphragms include internal channels which, together with the impellers, form a flow duct of the compressor.
A typical diaphragm includes a return channel, a plurality of blades or vanes, and a diaphragm wall that are bolted together. Both turbines and compressors usually include such diaphragms. For instance, U.S. Pat. No. 3,330,180 to Tuttle et al. discloses a diaphragm assembly for use with a turbine. The diaphragm assembly includes an outer retaining ring and a concentric, inner retaining disc. The retaining ring and disc are each split along the same horizontal plane. Accordingly, the retaining ring includes ring segments and the disc includes segments. The segments are coupled together with screws that extend through an oversized bore segment into a threaded bore segment. The diaphragm assembly further includes nozzle blade segments that extend between the radial inner surface of the retaining ring and the periphery of the disc. U.S. Pat. No. 3,367,630 to Saunder discloses a similar configuration.
However, such prior art diaphragm configurations suffer from various deficiencies. First, such diaphragms include a large number of parts that must be assembled using specialty bolting. Accordingly, prior art diaphragm assemblies have been expensive to manufacture due to the large number of parts and the expensive specialty bolting required. In addition, such diaphragm assemblies are difficult to disassemble, thereby making cleaning of the assemblies problematic.
Therefore, a need exists for a diaphragm assembly for use with a centrifugal compressor that includes a minimum number of parts that can be quickly and easily assembled without the use of expensive specialty bolting. In addition, a further need exists for a diaphragm assembly that can be easily disassembled, thereby allowing for easier cleaning of the diaphragm assembly.